Throughout the HIV epidemic, volunteers and volunteer service organizations have played critical roles in caring for persons living with HIV and AIDS (PWAs) and in educating the public about HIV disease. The proposed research builds programmatically on and expands the scope of the research team's previous work on the social and psychological aspects of AIDS volunteerism to develop a theoretical conceptualization that embeds volunteer-PWA helping relationships in the broader context of the community of people affected by HIV. This conceptualization stresses the resources, social support, positive identification, and increases in efficacy that result from a strong psychological sense of community. The specific aims of the proposed collaborative research are to investigate the roles of psychological sense of community in: (1) optimizing the recruitment of new volunteers by AIDS service organizations (ASOs), (2) promoting the physical and psychological functioning of PWAs, and (3) increasing the satisfaction, effectiveness, and persistence of volunteers. Two large scale, coordinated, multi-site, field based intervention studies will systematically address these aims. In the first intervention study, potential AIDS volunteers will receive either a standard recruitment message or one that makes salient the community context and connection of volunteering. It is hypothesized that the community message will effectively promote AIDS volunteerism, as measured by attitudes, intentions, and actual volunteer behavior, especially among individuals who have previously shown a propensity to support the ASO through participation in a fundraising walk. In a second linked intervention study of an experimental client service program, pairs of volunteers and client PWAs in ASOs will be randomly assigned to one of three conditions: (1) a standard treatment control condition, (2) a 6-month structured intervention designed to build a psychological sense of community, or (3) a 6-month attention control condition. Measures of the psychological and physical functioning of client PWAs and of the attitudes and performance of volunteers are expected to demonstrate the immediate and long-term effects of the community intervention. This multi-level collaborative approach -- examining AIDS volunteerism at the level of individual volunteers and PWAs as well as in the context of organizations, social networks, and community -- has the potential to increase theoretical understanding of voluntary helping relationships and psychological sense of community. The research also has the potential to contribute to the practically important issues of enhancing the effectiveness of volunteer recruitment programs, promoting the psychological and physical health of PWAs, and increasing the satisfaction and effectiveness of volunteers.